LI Cong-ni,LI Jun-li,LI Ji-yang,HUANG Jin,ZHANG Ying.Properties and Mechanism of Alcohol-ether-based Dimidazoline Corrosion Inhibitor[J],49(8):302-308
Properties and Mechanism of Alcohol-ether-based Dimidazoline Corrosion Inhibitor
Received:October 28, 2019  Revised:August 20, 2020
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DOI:10.16490/j.cnki.issn.1001-3660.2020.08.035
KeyWord:corrosive inhibiter  alcohol ether carboxylic acid  dimidazoline  polarization curve  corrosion inhibitor  isothermal adsorption
              
AuthorInstitution
LI Cong-ni 1.Shaanxi Research Design Institute of Petroleum and Chemical Industry, Xi¢an , China; 2.Shaanxi Provincial Key Laboratory of Petroleum Fine Chemicals, Xi¢an , China
LI Jun-li 1.Shaanxi Research Design Institute of Petroleum and Chemical Industry, Xi¢an , China; 2.Shaanxi Provincial Key Laboratory of Petroleum Fine Chemicals, Xi¢an , China
LI Ji-yang 1.Shaanxi Research Design Institute of Petroleum and Chemical Industry, Xi¢an , China; 2.Shaanxi Provincial Key Laboratory of Petroleum Fine Chemicals, Xi¢an , China
HUANG Jin 1.Shaanxi Research Design Institute of Petroleum and Chemical Industry, Xi¢an , China; 2.Shaanxi Provincial Key Laboratory of Petroleum Fine Chemicals, Xi¢an , China
ZHANG Ying 1.Shaanxi Research Design Institute of Petroleum and Chemical Industry, Xi¢an , China; 2.Shaanxi Provincial Key Laboratory of Petroleum Fine Chemicals, Xi¢an , China
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Abstract:
      The work aims to solve the corrosion problem of low carbon steel equipment due to CO2 in the whole injection- production and surface gathering and transportation system by simulating CO2 intensive extraction process and studying the corrosion inhibition performance and mechanism of alcohol-ether-based dimidazoline DIM-OE. The molecular structure of alcohol-ether-based dimidazoline was characterized by Fourier infrared (FTIR) spectroscopy. The corrosion inhibition perfor-mance of DIM-OE to N80 at different CO2 partial pressure, different temperature and different mass concentration was evaluated by dynamic hanging method. The electrochemical mechanism of DIM-OE was studied by potentiodynamic polarization curves. The surface morphology and element content of N80 after corrosion were analyzed by scanning electron microscope (SEM) and Energy Dispersive Spectrometer (EDS). The corrosion rate of N80 increased significantly with the increase of CO2 partial pressure, but increased firstly and then decreased obviously with the increase of corrosion medium temperature. As the concentration of DIM-OE increased, the corrosion rate decreased gradually, the corrosion inhibition rate increased gradually, and finally tended to be stable. The minimum corrosion rate was 0.063 mm/a, and the corrosion inhibition rate was all above 90%. DIM-OE was a mixed corrosion inhibitor mainly inhibiting anode, and the adsorption of its molecules on N80 surface was monolayer adsorption, which was the interaction of physical adsorption and chemical adsorption. The weight percentage of C and O elements in N80 surface corrosion products without DIM-OE was high, and the weight percentage of Fe elements was low, so the corrosion was serious. The weight percentage of C and O in N80 surface corrosion product with 200 mg/L DIM-OE was lower, the weight percentage of Fe was higher, and the corrosion was lighter. Under the condition of CO2 intensive extraction, the DIM-OE corrosion inhibitor can form a stable adsorption layer on the surface of N80 and effectively inhibit the corrosion of N80 steel sheet by CO2 and have good corrosion inhibition effect.
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